This invention relates to the fields of angioplasty and other interventional procedures. More particularly, this invention relates to improved catheter-based systems for stent delivery.
Balloon dilatation catheters have been used to dilate various types of strictures in blood vessels and other body lumens for over twenty years. Typically, such catheters comprise a balloon mounted on the distal end of an elongated flexible shaft and an inflation tube or lumen extending longitudinally within the shaft from its proximal end to the interior of the balloon. Among the major advancements in balloon dilatation catheters has been the development of smaller catheters that can be used in smaller and/or more distal anatomical locations, and the development of catheters that can be rapidly exchanged. Examples of such catheters are described in U.S. Pat. No. 4,748,982 (Horzewski), U.S. Pat. No. 4,762,129 (Bonzel), U.S. Pat. No. 5,040,548 (Yock), U.S. Pat. No. 5,061,273 (Yock), U.S. Pat. No. 5,569,199 (Solar) and U.S. Pat. No. 5,728,067 (Enger). Because these catheters have become more sophisticated and complex in design, and despite the manufacturers"" experience in manufacturing them, these catheters are expensive to make. Furthermore, despite these improvements, difficulties are still encountered in advancing catheters through tortuous anatomy and safely crossing very tight strictures and stenoses in the vascular system and other body lumens or cavities.
Recently vascular stents have been shown to play an important role in reducing the restenosis rates associated with balloon angioplasty. However, stents are sometimes lost from the delivery systems and are difficult to retrieve safely. Thus, there is a need for an enhanced stent delivery system.
It is an object of the invention to provide an enhanced delivery system that is extremely low-profile to more easily and safely cross very tight strictures and stenoses in the vascular system and other body lumens or cavities.
It is also an object of the invention to provide an enhanced delivery system that provides for an improved means for crossing tight stenoses, as well as to navigate tortuous anatomy.
It is another object of the invention to provide an enhanced delivery system that has the ability to be exchanged rapidly.
It is yet another object of the invention to provide an enhanced delivery system that can be used to retrieve dislodged stents.
It is a further object of the invention to provide an enhanced delivery system that can be manufactured inexpensively and more reliably then currently available stent delivery systems.
It is also an object of the invention to provide an enhanced delivery system that allows placement of an additional catheter or instrumentality adjacent to a catheter.
It is likewise an object of the invention to provide an enhanced delivery system that facilitates placement of stents or stent grafts.
It is a yet further object of the invention to provide a delivery system that enhances retention of stents or stent grafts in corporeal vessels or cavities.
These and other objects of the invention will become more apparent from the discussion below.
According to the invention, an enhanced stent delivery system comprises an elongated advancement member which optionally terminates in a tubular tracking member, and an inflatable balloon having proximal and distal ends, which enhanced stent delivery system is useful for placement of stents and stent grafts. The proximal end of the inflatable balloon is in fluid communication with an inflation channel, and the distal end of the inflatable balloon is attached to the tubular tracking member or the advancement member. During advancement of the system, the inflatable balloon and inflation channel are somewhat coextensive with the advancement member. The system is slidable over a guidewire.